Epidemiology and clinical features of homicide

Prof. Olav Nielssen1

1Macquarie University, Sydney, Australia

It was previously believed that homicide by the mentally ill, or abnormal homicide, occurred at a constant rate and was linked to the epidemiology of mental illness, that the rates did not change over time, and also the homicide was associated with chronic schizophrenia and could occur at any time during the illness. A series of recent studies have demonstrated that homicide in mental disorder is in fact closely linked to the overall rate of homicide in the community, that the rates do vary according to the efficacy of mental health services and other social factors, and that first episode of psychosis, between the onset of symptoms and initial treatment, is the period of greatest risk for homicide in schizophrenia. The author will also present the results of original research on homicide-suicide, infanticide, child homicide, stranger homicide, homicide by the elderly and homicide recidivism. The presentation will review the clinical features of mentally disordered and mentally ill offenders who commit homicide, and the circumstances in which those offences occur, and discuss measures by which the rates of homicide might be further reduced.


Professor Nielssen is a coauthor of the chapter on homicide in the forthcoming Oxford Textbook of Psychiatry. He has personally assessed more than 500 homicide offenders, and has published more than 150 papers in peer reviewed journals, many of which were on aspects of homicide and related topics.